What term describes something that is large and heavy or solid?

The term "massive" is particularly suited to describe something that is large and heavy or solid because it specifically conveys the idea of considerable weight and bulkiness. When something is referred to as massive, it implies that it is not only large in size but also has a significant density or weight, which aligns perfectly with the notion of being solid.

While "substantial" can indicate a meaningful amount or degree, it doesn’t exclusively connote size or heaviness. "Voluminous" refers more to something that takes up a lot of space or has a lot of volume, which isn’t the same as being heavy or solid. "Enormous" certainly suggests great size, but it doesn't inherently imply heaviness or solidity in the same way that "massive" does. Thus, "massive" best captures the essence of being both large and heavy or solid.